Cable sheath seam welding

ABSTRACT

A seam-welding method for metal tubes displaces the welding electrode from a normal position with respect to the tube to a position over an auxiliary electrode. Current is initiated between the welding electrode and auxiliary electrode which is removed and the current increased, with the welding electrode being returned to the normal position.

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority Colin Francis Greening Smith' llants, England 558,900

June 20, 1966 Aug. 17, 1971 International Standard Electric Corporation New York, N.Y. June 25, 1965 Great Britain CABLE SHEATH SEAM WELDING Field 0! Search 4 Claims, 2 Drawing Figs.

US. Cl. .Q 2 19/61,

Int. Cl. 823k 9/02 219/60, 6l,

[56] References Cited UNITED STATES PATENTS 1,512,787 10/1924 Morton .l 219/137 1,616,145 2/1927 Shipman..... 2l9/147X 2,682,598 6/1954 Macoy.... 219/61 2,957,977 10/ 1960 Sullivan 219/137 X 3,226,522 12/ 1965 Duddridge et al. 219/60 Primary Examiner-J. V. Truhe Assistant Examiner-J. G. Smith Attorneys-C. Cornell Remsen, Jr., Rayson P. Morris, Percy P. Lantz, Philip M. Bolton and lsidore Togut ABSTRACT: A seam-welding method for metal tubes displaces the welding electrode from a normal position with respect to the tube to a position over an auxiliary electrode. Current is initiated between the welding electrode and auxiliary electrode which is removed and the current increased, with the welding electrode being returned tothe normal position.

already welded portion while the tube is stationary a predetermined relative displacement from a normal welding position in a first direction parallel to theedges of the folded strip, interposing an auxiliary electrode of a-material of relatively high thermal conductivity between said tube and said welding electrode at the displaced position, then initiating a flow of current between said welding electrode and said auxiliary electrode, removing said auxiliary electrode on initiating relative movement in a direction opposite to said first direction between said tube and said welding electrode, increasing said current and initiating flow thereof between said welding electrode and tube to a value suitable for causing the seam of said tube to be welded and causing a second displacement to return said welding electrode to said normal position, said movement of said tube past said welding electrode being continued to weld said seam.

2. A method of seam welding a metal tube formed from a folded strip, said method including a starting operation which comprises the steps of causing a predetermined relative displacement from a normal welding position in a first direction parallel to the edges of the folded strip to occur between the tube and an arc welding electrode, interposing an auxiliary electrode of a material of relatively high thermal conductivity between said tube and said welding electrode at the displaced position, then initiating a flow of current between said welding electrode and said auxiliary electrode, removing said auxiliary electrode in a plane not including the tube or the welding electrode from between said tube and said welding electrode on initiating relative movement in a direction opposite to said first direction between said tube and said welding electrode,

increasing said current and initiating flow thereof between said welding electrode and .tube to a value suitable for causing the seam of said tube to be welded and causing a second displacement equal and opposite to said predetermineddisplacement to return said welding electrode to-saidmormal position, said movement of said tube past said welding electrode being continued to weld said seam. J a 1 3. Apparatus for seam welding a metalftubeformed from a folded strip which comprises means for folding tsaid strip, an arc welding electrode mounted adjacent the edges of the folded strip, said tube having a normal movement relative to said folding means and electrode in one direction parallel to the edges of the folded strip and adapted to have a predetermined displacement from a normal welding position in a direction opposite to said one direction, an auxiliary electrode having a flat portion interposed between the tube and the welding electrode and including means for removing the auxiliary electrode in a plane not including the tube or the welding electrode, the auxiliary electrode being made of a material of relatively high thermal conductivity, means applying a potential between the welding electrode and the auxiliary electrode and tube, the auxiliary electrode being removable from between the tube and the welding electrode on initiating relative movement in said one direction, said welding electrode being returned to said normal position upon application of sufficient potential suitable for welding.

4. Apparatus as claimed in claim 3, wherein said means for removing the auxiliary electrode is an armature mechanically coupled thereto. 

1. A method of seam welding a metal tube formed from a folded strip, said method including a starting operation which comprises the steps of moving a welding electrode opposite an already welded portion while the tube is stationary a predetermined relative displacement from a normal welding position in a first direction parallel to the edges of the folded strip, interposing an auxiliary electrode of a material of relatively high thermal conductivity between said tube and said welding electrode at the displaced position, then initiating a flow of current between said welding electrode and said auxiliary electrode, removing said auxiliary electrode on initiating relative movement in a direction opposite to said first direction between said tube and said welding electrode, increasing said current and initiating flow thereof between said welding electrode and tube to a value suitable for causing the seam of said tube to be welded and causing a second displacement to return said welding electrode to said normal position, said movement of said tube past said welding electrode being continued to weld said seam.
 2. A method of seam welding a metal tube formed from a folded strip, said method including a starting operation which comprises the steps of causing a predetermined relative displacement from a normal welding position in a first direction parallel to the edges of the folded strip to occur between the tube and an arc welding electrode, interposing an auxiliary electrode of a material of relatively high thermal conductivity between said tube and said welding electrode at the displaced position, then initiating a flow of current between said welding electrode and said auxiliary electrode, removing said auxiliary electrode in a plane not including the tube or the welding electrode from between said tube and said welding electrode on initiating relative movement in a direction opposite to said first direction between said tube and said welding electrode, increasing said current and initiating flow thereof between said welding electrode and tube to a value suitable for causing the seam of said tube to be welded and causing a second displacement equal and opposite to said predetermined displacement to return said welding electrode to said normal position, said movement of said tube past said welding electrode being continued to weld said seam.
 3. Apparatus for seam welding a metal tube formed from a folded strip which comprises means for folding said strip, an arc welding electrode mounted adjaCent the edges of the folded strip, said tube having a normal movement relative to said folding means and electrode in one direction parallel to the edges of the folded strip and adapted to have a predetermined displacement from a normal welding position in a direction opposite to said one direction, an auxiliary electrode having a flat portion interposed between the tube and the welding electrode and including means for removing the auxiliary electrode in a plane not including the tube or the welding electrode, the auxiliary electrode being made of a material of relatively high thermal conductivity, means applying a potential between the welding electrode and the auxiliary electrode and tube, the auxiliary electrode being removable from between the tube and the welding electrode on initiating relative movement in said one direction, said welding electrode being returned to said normal position upon application of sufficient potential suitable for welding.
 4. Apparatus as claimed in claim 3, wherein said means for removing the auxiliary electrode is an armature mechanically coupled thereto. 